The toxicity of trace heavy metals found in drinking water, food, and the environment is an area of increasing national and international concern. Heavy metals are significant environmental pollutants because they tend to persist, tend to bioaccumulate and can result in serious adverse health effects when ingested or inhaled. Measurement of human exposure in the population serves in determination of safe regulatory exposure limits and prevention of diseases caused by heavy metals. Trace metals can be measured in human tissue or fluids such as blood or urine in centralized laboratories using complex analytical methods such as high-performance liquid chromatography inductively coupled plasma mass spectroscopy. However, in view of the high labor and analytical costs and long time delays associated with centralized laboratory analyses, there is an immediate need for a portable and inexpensive system for on-site monitoring of human exposure to heavy metals. The overall objective of this project is to develop a portable, self-contained, easy-to-use monitor for simultaneous on-site measurement of arsenic, cadmium, manganese and lead metals from a single urine sample, in near real time, to assess personal exposure. The proposed sensor combines a specialized electrochemical measurement technique with a unique microarray electrode material and configuration for unprecedented sensitivity and selectivity, under real-world operating conditions. During Phase I, Giner, Inc. developed sensor design configurations, electrode material compositions, and operating conditions which demonstrated the feasibility of the unique microchip sensor prototype for the detection of arsenic and cadmium species at 0.2 ppb level in water. Testing in urine is ongoing in the Phase I program, with arsenic and cadmium detected in the initial studies at 100 ppb with a response magnitude indicating a lower detection limit will be attained in the last four months of Phase I. The Specific Aims of this intensive Phase II program encompass design, fabrication and validation testing of a prototype field-portable analytical system for detection of a broader range of heavy metals (including arsenic, cadmium, manganese and lead) at concentrations in the relevant ppb and sub-ppb levels in water and in urine. The performance of the monitor will be extensively characterized for sensitivity, selectivity, robustness and ease-of-use in real-world samples and field situations. During the Phase II program, five prototype compact packaged units will be fabricated for use in ongoing epidemiological studies in three field locations (Bangladesh, Tar Creek, OK and Mexico City) in collaboration with Harvard School of Public Health. Subsequent to Phase II, the five prototypes will be ready for use in additional field research prior to its introduction as a commercial product for multiple markets in research, environmental and health monitoring. PUBLIC HEALTH RELEVANCE: Human exposure to toxic heavy metals is common in the U.S. and internationally with serious adverse health effects. This Phase II SBIR research is for development a portable monitor for measuring toxic metals (arsenic, cadmium, lead and manganese) in the urine as a way to rapidly, inexpensively assess personal exposure. A portable field monitor will facilitate the ease, rapidness and cost-effectiveness of public health monitoring and research studies to understand the relationship between chemical exposure and disease outcomes.